LSJ GMS3 Questions/Troubleshooting.
 

Question for a few of the more knowledgeable LSJ folks.

First, When tuned with GMS3 (or Trifecta stage 3) how do you adjust the rev limiter?

Second, With ZZP STAGE 3 with the HE and smaller pulley (2.8 i think) what temp's should the IAT2's be at?

IAT2's depend on outside temp as well

and turn the key to ACC then push the pedal to what u want the limit to be

Oh awesome.

it was about 70-80 degrees F if i am not mistaken.

This.

The rev limiter will increase in 250rpm increments from 6,500rpm - 8,000rpm.

When you want to set the limiter, hold the gas pedal at desired revs and turn the key off. To check the new limiter turn the key back to ACC and slowly depress the gas pedal. It should now read your new limiter.

Do not adjust the limiter above 7,250rpm unless you have upgraded valve springs, and do not adjust the limiter past 7,500rpm w/o NB Shafts.

(Waits for people to say they have been fine reving past the limits I posted with out upgrades.)

The person i am tuning is going to 7200

That's fine. He should be good.

My rev limiter has been set to 7,250rpm since I installed my GMR Stage 3 kit 3 years ago.

Is it normal to have 161* IAT2 temps well running down the track on a 70-80 degree night? with a upgraded HE?

161* is def high.

At the end of 3rd I usually top out around 145-150ish on a hot night/day. It's tough to compare IAT2's though. What size pulley is on the car, along with mods?

Its not my car, its a customer i am tuning with Trifecta. He is noticing kr of 4.5-5 on track night and as high as 7.

On the run his iat's were 161. He notices 105-110 well on the highway (which sounds normal)

Just trying to solve the problem of the high KR. I am not very fimilar with LSJ's and such.

I believe above 140ish IAT2's the car will begin to pull timing (on a GMS3 tune).

Cruising he should be seeing around 15-20* above ambient. So, for example, if his IAT1 is 80 a IAT2 temp of around 100*F would be acceptable.

7*KR is not good at all. Either his intercooler pump is starting to shit the bed, or some other lying issue is causing the problem. The GMS3 tune as it comes from GM commands some fairly aggressive timing. I have logged my timing around 22-23 degrees in 2nd gear, and 20-21 degrees in 3rd gear. Is your customers car running the GMS3 pulley, or a smaller one?

Could it be the tune? To agreesive? pulling to much timing?


My customer tells me his IC pump was broken once but is fixed now.

Too much timing can def cause KR, but if he is running the GMS3 hardware his car should be fine. Do you know what modifications he has?

Sorry, I just read the first post again. He has a 2.8 pulley. Is he running the 2.8 pulley with the GM 42 lb/hr injectors?

He has the ZZP Stage 3 kit with the Trifecta GMS3 tune.

Ok, so his fueling should be fine. That kit comes with 60's.

Hmm, see it's tough for me to figure out the issue, because I don't know what he had altered in the Trifecta GMS3 tune. I run the GM Racing Stage 3 tune, but it's not altered by Trifecta other than unlocked A/C.

Since you are going to tune him check to see what his timing advance is set at. Does he have a wideband? Ask him to check his A/F ratio.

For shits and giggles ask him what kind of fuel he is using. I hope he is running 93 octane.

We only have 91 here in canada. Any other is 93 with 10% corn fuel.

He does not have a wideband. He plans to get one just does not have the funds for it currently.

Good point on the fuel. I will let Vince at Trifecta know.

I bet that is part of his issue. The base GMS3 file requires 93 octane.

Yeah i am thinking we have narrowed down the issue. Thanks so much for the help.

No prob man. Let me know how you make out.

So we re-dataloged the customer. Vince said the logs looked good except for the fact that he is pulling lots of knock and his IAT2 temps were reaching near 200*F on a pull.

Is there any reasons at all why those temps would be well over 100* above ambiant temps?

1. Bad pump
2. Trapped air in the intercooler system

You mentioned he replaced the pump recently, so I would check to see if he has air trapped in the coolant.

Okay.

Doesnt 160 seem high for right after a run down the track at 70-80*F ambiant temps with a stage 3 (ZZP) Heat exchanger to be working correctly?

I mean, In the turbo world my iat2 temps never ever climb that high, I know superchargers generate a lot more heat but i really did not think it would be THAT bad.

if you want the real truth you shouldent spin a lsj past 6500 on the stock balancer the stock balancer dosent do a thing for the engine after that besides start shaking shit loose so if you want to be safe get the ati balancer

and i am guilty of spinning stock valve train to 8000 a couple of times on the dyno and spinning it regulary to 7500 even with the pos stock balancer

If you could, you should chime in on our local thread (manitoba 2011) Yellow_dragon is the one that i am tuning with zzp stage 3.

Yeah, 160*F is getting pretty high (he is running a 2.8" pulley though). What was the humidity like?? I know my car's IAT2's can vary on 80*F days if the humidity is real shitty.

Last night was a crispy 70* with a wind. Hardly any humitidy. However it can get humid on days.